Light micrograph of a group of protoplasts from a tobacco leaf, Nicotiana sp. A protoplast is a single intact cell, which has been chemically treated to remove the tough outer cellulose wall, leaving only the delicate plasma membrane binding the cell contents into a whole. The cell wall can later be regrown. The cells contain chloroplasts (green), the sites of photosynthesis. Protoplasts, lacking the tough wall, are easier to manipulate. They are used in plant genetic engineering, including work on hybridization & disease resistance. The techniques used in protoplast technology are pertinant to biotechnology & medicine. Magnification X100 (at 35mm size).